I had to add my husband's middle initial to his CO account because it was on his UA account. I had no problems doing so.

My UA (MP) account just has my first and last names (SMITH/JOHN). My CO (OP) account has me listed as Mr. John Smith which turns into SMITH/JOHNMR on tickets. (That isn't my middle initial, which neither airline uses.) Early this year the accounts wouldn't merge, but later they did, with no input from me except for trying to merge them automatically online every few months.

You men. Don't ever get married and have to change your names. It is a PITA. I wasn't going to change mine but my DH got offended. Of course he did not have to change his name on every single thing that had a legal name on it.

Just call CO or UA and ask for what proof of name change they want and ask for the specific address or fax you need to send it to.

You will need some proof of name, passport, marriage license, etc.

You will have to show old name or error and provide proof of naming correction.

It does require supporting documentation, they will NOT just change it over the phone.

CO Credit Card Saves the Day!
 

I saw this thread and figured I better work on linking my two accounts. My MileagePlus account was "Firstname I Lastname, Jr." My OnePass account was in the name of "Firstname Lastname." I thought the "Jr." would be a problem, seeing this thread. I called CO anyway, and the agent thought it would be a problem, but she saw that my CO credit card had both the middle initial and the Jr., so problem solved.

She changed the name on the CO account to match the MileagePlus account and all was well.